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You then need some way of doing the same with the data source for the chart featured in the ppt. And then this of course all depends on where the data is coming from. It may not even be that you need to get the ppt if the data source is, in fact, coming from an external db, for example. If the graph/chart points at an access or sql database your job is made a lot easier:

This would be added by a user wanting manipulate a chat on that page.
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user1696976Sep 25 '12 at 11:03

I don't understand your comment, or the edit to the OP. You mention 'new chart' yet the idea of getting an existing chart. I'm going to assume you mean you want to get a chart already in the ppt and alter it's data source. Again - you haven't narrowed it down enough. How are they going to change the data source? Datagrid view? What assumptions are you making about the origin of the existing data? Narrow your problem down into small issues - so specific that there's no way they can be unclear, then post on SO (providing you have tried something first and the question doesn't already exist).
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JayMeeSep 25 '12 at 11:08

The data would be coming from an iput form to aloow the users to change the chart
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user1696976Sep 25 '12 at 11:15

You know you have many many questions surrounding this 'one' problem. What I'm proposing is that you categorise these questions into individual tasks. Attempt to crack them, and if you have no luck - ask a more specific question on here. You won't be spoon fed throughout your entire project if you don't show an efficient asking style and a willingness to help yourself and at least have an attempt. You've shown no code so far. Dismiss my advice if you like, but the absence or anyone else's comments and answers stands to make my point. Good luck, I'll try my best to help when you come back.
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JayMeeSep 25 '12 at 12:52